DSP + FPGA: digital signal processing module for wireless communication systems

Project overview

Challenge 

Our task was to design a versatile FPGA module for digital signal processing (DSP) to be used in telecommunication systems, transmitters of digital TV and radio, radar complexes, wireless communication systems, and software-defined radio systems (SDR).

We were to provide software support for 17 protocols and communication standards: 802.11 (b, g, n), 802.16, GSM, WCDMA, TETRA, APCO, ZigBee, WiMAX, Bluetooth, OFDM, ISM 2.4, LTE, SISO + MIMO, RFID, DVB, DRM.

Solution 

We have designed a DSP + FPGA platform with an open architecture for wireless communication systems based on the SDR technology. The main board was based on TMS320C6674, a 4-core processor by Texas Instruments (1.25 GHz).

The platform architecture includes three modules:

1. A DSP module for digital signal processing algorithms and data exchange via communication interfaces: Serial RapidIO, Hyperlink, PCI Express, Gigabit Ethernet, SGMII, RS-232, SPI, I2C.
2. A receiver/transmitter module for analog-to-digital conversions and primary processing of low-frequency signals. It includes programmable Xilinx Spartan-6 FPGA, high-speed ADC and DAC. 
3. An RF module with 150—2200 MHz of carrier frequencies, and variable bandwidth up to 40 MHz.

Areas of application for the DSP+FPGA С6674-S6 platform:

• Video surveillance and conference communication systems
• Solutions for the security sector
• Last-mile communication systems
• Digital TV and radio
• Cellular communication
• Smart grid
• Radio-frequency identification scanners (RFID)
• Multi-sync systems, etc.

Here are a few examples of specific projects based on this high-end FPGA processing board:

1. Design of a high-speed satellite modem
2. FPGA software for HD 4K framebuffer
3. IP core for QSPI flash emulation

Business Value

With the C6674-S6 DSP+FPGA board, our client can implement the latest telecommunication standards and protocols without significant investment in hardware design, focusing on the development of specific software and algorithms only. 

Open modular architecture and software-defined radio transceiver significantly reduce the time for the development, testing, and implementation of hardware and software solutions for wireless communications.

Media coverage of the project

1. EE Times Europe: Designing a universal software defined radio platform
2. EE Times Europe by Julien Happich (editor-in-chief): Promwad unveils turn-key electronic solutions based on TI’s products

How it's made

The architecture of the FPGA digital signal processing module

1. A signal processing module is based on the ТМS320C6674 processor,  a quad-core 1GHz DSP by Texas Instruments. It enables high-speed data exchange with external devices.

DSP TMS320C6674	1 GHz
RAM, DDR3	512 MB
Flash, NAND FLASH	512 MB
Dimensions	180x80 mm
Power	DC 12В±30%
Operating temperature	−30 … +55 ºC
Storage temperature	−40 ... +85 ºC

2. A receiver/transmitter module includes programmable logic of the Xilinx Spartan-6 FPGA, high-speed DAC and ADC. It provides the following interfaces for external connectivity: Serial Rapid IO, SPI, analog input and output.

FPGA	Xilinx Spartan 6
ADC ADS62P49	Dual Channel 14 bit, 250 MSPS
DAC3283	Dual Channel 16 bit, 800 MSPS
RAM, DDR3	128 MB
ROM, NAND FLASH	32 MB
Interfaces	Serial Rapid IO, RS232
Dimensions	180x80 mm
Operating temperature	−30 … +55 ºC
Storage temperature	−40 … +85 ºC

3. An RF module for direct frequency conversion, carrier frequency 50–2200 MHz and variable bandwidth up to 40 MHz.

TX/RX power (at least)	100 mW
Sensitivity at 40MHz band (at least)	−60 dBm
Band (at least)	40 MHz
Frequency tuning	10 kHz
Frequency range	150—2200 MHz
Receiver selectivity (not less)	40 dB
Noise ratio (not more than)	10 dB
Power	DC 12В±30%
Operating temperature	−20 … +50 ºC
Storage temperature	−40 … +85 ºC